Your timeline settings don’t match your video that is on the timeline. BM should have an easy setup for the project that matches your footage. Use that so you don’t have to set everything manually.
The mp3 will always need to render.
BTW never use the system hard-drive. Really not a good idea. Always put your media on a separate drive. Make sure that drive is formated HFS+ Extended but NOT journaled! The system drive must be journaled but journaling will cause issues down the road with media.
Hope this helps-
Matthew
Dual 500 G4
OSX 10.3.9
Ram 1.38
FCP 4.5/AE 6.5/DVDSP3